Antenna heights of 50 and 100 feet do not improve signal strength , so a Winegard HD7694P antenna mounted above the roof will be Ok. I recommend a Channel Master CM3414 4 way distribution amplifier. Here are some places to buy Tv antennas and etc. , ,
http://www.solidsignal.com ,
www.starkelectronic.com ,
http://www.amazon.com . 15 to 20 feet above the ground will be better for reception.